Analog vs. Digital – What’s the Difference?

We live in an analog world, all that we see, all that we hear, all that we taste is analog. Digital is our best approximation of the analog world, one sample at a time. If our samples are close enough together, our approximation is almost perfect, if our samples are further apart we start missing details.

Digital is on/off. Analog is on/off and all the possibilities between. Take light as an example.

A simple toggle light switch (digital) turns the light full-on or off, light or no light. A slider lighting control (analog) allows the light to range anywhere from full-on to off and all the range of brightness between.

Since analog contains all the possibilities between on and off, it represents a great deal more information than just on/off. So if all the information is in analog, why not always work strictly with analog signals?

Because processing data, making decisions, and storing information is in general more easily and efficiently done by digital controllers and computers using digital signals. Because of this, the analog world is often converted to digital when making complex decisions.

However, to shift from operating in the analog world to digital requires some compromise, loss of information. Conversion from analog to digital is done with a series of single points of data that do not represent all the possibilities of analog, but a bunch of them.

The number of single points used to represent the analog world depends on how closely the digital representation needs to match. Requirement for a very close match can result in a huge number of data points to the point of straining capability of the digital processing capability.

Therefore a balance is required and there is cause for both analog and digital processing to be used.

Is analog better than digital?

Analog and digital both have their place and the decision to use one, the other, or both is based on a number of factors

  • Cost
  • Accuracy
  • Processing requirements
  • Flexibility
  • System demands of using one vs the other

Nature is an analog system, our brain processes all inputs, stores information and makes decision in analog domain, unfortunately we do not yet have the technology that could fully emulate nature’s analog performance. Until we do, we are limited to a hybrid solution.

We use analog technology as an interface between the real world around us and digital world that computers can interpret and process. We receive concert sound using analog technology, we sample this sound to produce its digital representation. We store this sound in digital domain, iPod, and when we want to hear playback of previously stored track, we use analog technology to translate stored signal from digital world back to analog world, our ears can understand.